This may be the only question in this series to which the answer is "no".

It's not obvious that you can't have too many ethics. Like every other word, it's used to conceal the truth as well as to point towards it, and in some corporate meanings "ethical" is, and ought to be, a warning sign.

"Ethical" in the corporate sense is something much more like "pious", although without the Christian underpinning. Perhaps we need a word for the resulting vain self-satisfaction – ethicity, after the model of piety. This would cover fair trade, sustainability, the ostentatious avoidance of sweatshops and so on. It is the kind of thing of which oil companies boast, and Google.

This isn't actually always a bad thing. It's better than unbridled vice. The Scott Trust is an improvement on Richard Desmond, who famously said he had no idea what the word "ethics" means. But it is possible to have too much ethicity. Google is a pretty good example, as is much of the culture of Silicon Valley. Good behaviour isn't always something you can buy with money. Still less is it something you can buy with money you have made through ruthless libertarian selfishness.

Another form of too much ethics is shown by some forms of utilitarianism which proceed from apparently reasonable premises to obviously monstrous conclusions. The two Australian ethicists who in 2012 argued that there was nothing wrong in killing newborn babies if their existence inconvenienced their parents are a poster case for this. So is the reaction of the editor who published the paper:

"What is disturbing is not the arguments in this paper nor its publication in an ethics journal. It is the hostile, abusive, threatening responses that it has elicited. More than ever, proper academic discussion and freedom are under threat from fanatics opposed to the very values of a liberal society."

When "ethics" becomes a term for a style of reasoning about moral questions which leads its adepts to monstrous conclusions, yes, we can certainly have too much of it.

Much the same could be said for some forms of Roman Catholic bioethics. Beyond that is the general problem of pharisaism, where ethical reasoning comes to be a way of demonstrating the cosmic significance of the mote in your opponent's eye.

In all these cases it looks as if you can be entirely too ethical and anyone who complained of this would be instantly understood. But when you look at the complaint more closely, it actually means that someone has acted wrongly in their display of ethicity, or rule-based smugness – and to act wrongly is by definition unethical. So what looks like to much ethics is in fact too little.

This makes most sense in the context of Aristotelian reasoning about virtues, where the virtuous position is balanced between two vices, so that either too much or too little is a flaw in your character. The essence of virtue, then, is moderation, or perhaps just proportion. Framing it this way avoids the obvious retort – so often heard in discussion of ethics here – that you can have far too much moderation because you can't have too much justice. And neither, properly speaking, can we ever be too ethical. We're lucky if we can just be ethical enough.